A robust narrowband to wideband extension system featuring enhanced codebook mapping

It is well-known that wideband speech (0-7 kHz) provides better quality and intelligibility than narrowband speech (300-3400 Hz), but typically only narrowband speech information is available in current wireless communication systems. Narrowband to wideband extension technology has been recently investigated to artificially generate wideband speech from narrowband speech for better speech quality and intelligibility. This paper presents a robust split-band narrowband to wideband extension system based on algorithmic enhancements to the codebook mapping technique for high-band parameter estimation. Numerical measurements confirm the performance improvements of the codebook mapping process, and informal listening evaluations show the potential of the system and its robustness to input distortions and non-speech input signals.